Trifluorostannite salts of amines in oral compositions for caries prophylaxis



having special utility in caries prophylaxis.

United States Patent 3,201,316 TRIFLUOROSTANNITE SALTS 0F AMINES IN ORAL COMPOSITIONS FOR CARIES PRO- PHYLAXIS Paul E. Norris, Cincinnati, Ohio, assignor to Procter 8: glamble Company, Cincinnati, Ohio, a corporation of No Drawing. Filed Sept. 28, 1962, Ser. No. 227,044

Claims. (Cl. 167-93) This invention relates to a new class of compounds More particularly, it relates to trifluorostannite salts of amines and oral compositions for caries prophylaxis containing same.

By the term oral composition is mean a product which in the ordinary course of usage would not be ingested, but would be retained in the oral cavity for a time suflicient to contact substantially all of the dental surfaces. Such productsinclude, for example, dentifrices, mouthwashes, dental prophylaxis pastes and topical solutions.

- It is generally recognized that the introduction of small amounts of fluoride ion into drinking water has a pro- 'nounced 'elfect in reducing the occurrence of dental caries. Topical applications of aqueous fluoride solutions by dentists have provided an excellent measure of protection; Further, various other oral compositions such as toothpastes which contain fluoride ions in available form have proved to be highly useful for protection against the development of caries.

' A wide variety of inorganic fluoride compounds have been employed for caries prophylaxis. For example, sodium fluoride has been found to be a preferred watersoluble source of fluoride ion to use in drinking water. Stannous fluoride has been used with a great degree of success in topical application of oral compositions for caries prophylaxis, with both the stannous ion and the fluoride ion playing an important role in anticaries effeet by virtue of their ability to reduce the solubility rate of dental enamel. Organic fluorides such as amine hydrofluorides have also been suggested for use in formulations for caries prophylaxis.

i It is an object of this invention to provide a novel class of compounds which reduce the acid solubility rate of dental enamel.

It is a further object of this invention to provide improved oral compositions for caries prophylaxis, containing trifluorostannite salts of amines as anticaries agents. I These and other objects will become apparent from the following detailed description.

It has now been found that a new class of compounds which contain an amine moiety in addition to stannous and fluoride atoms is highly eflicacious in reducing the solubility rate of dental enamel in acid solutions. These compounds are also readily adaptable to formulation in a wide variety of oral compositions for caries prophylaxis.

The novel class of compounds of this invention are trifluorostannite salts of amines having the general structural formula:

R1 112- Ra wherein R R and R are each members selected from the group consisting of hydrogen, and alkyl, hydroxyalkyl and aminoalkyl radicals, at least one of said Rs being one of said radicals containing from about 1 to about 18 carbon atoms. Preferably the total carbon content of R R and R will be less than about 30 carbon atoms. In any event the compound must be sufliciently soluble to provide about 50 ppm. of analytically available fluoride ions in aqueous solution. Hydrophilic substituents such as hydroxyl radicals increase the solubility and permit radicals of greater chain lengths. Such substituted trifluorostannite salts are especially preferred for the purposes of this invention.

Compounds which are encompassed by the above general formula and which find utility in the compositions of this invention include the following:

(I) Salts of primary amines (A) Unsubstituted aliphatic amines Ethylamine trifluorostannite Isopropylarnine trifluorostannite Dodecylamine trifluorostannite Tetradecylamine trifluorostanriite Hexadecylamine trifluorostannite (B) Substituted aliphatic amines Ethanolamine trifluorostannite Isopropanolamine trifluorostannite 1,3-diamino-2-propanol .trifluorostannite Dodecanolamine trifluorostannite (II) Salts of secondary amines (A) Unsubstituted aliphatic Dimethylamine trifluorostannite Diethylamine trifluorostannite Diisopropylamine trifluorostannite Dodecylethylamine trifluorostannite Substituted aliphatic Diethanolamine trifluorostannite Ethylaminoethanol trifluorostannite Diisopropanolamine trifluorostannite Dodecylaminoethanol tn'fluorostannite Hexadecylaminoethanol trifluorostannite (III) Salts of tertiary amines (A) Unsubstituted aliphatic Triemethylamine trifluorostannite Dimethylaminopropylamine tiifluorostannite Triethylamine trifluorostannite Dodecyldimethylamine trifluorostannite Substituted aliphatic Triethanolamine trifluorostannite Methyldiethanolamine trifluorostannite Ethyldiethanolamine trifluorostannite 1-dimethylamino-2-propanol trifluorostannite N-octadecyl-N-hydroxyethyl-N di(hydroxyethyl)-propylene diamine trifluorostannite In general, the tr-ifluorostannite salts of amines which comprise one aspect of this invention are prepared by reacting an aliphatic amine with hydrofluoric acid and then reacting the resulting amine hydrofluoride with stannous iiuoride. The following example will illustrate procedures which can be used to prepare amine trifl-uorostannites. i

EXAMPLE I 30.6 g. of mono'ethanolarnine were added to 12 g. of

and one-half parts of distilled water and added slowly and with constant stirring to the amine hydrofluoride. The solution was concentrated to approximately half the original volume and refrigerated. A white crystalline product separated. The crystalline monoethanolamine tr-ifluorostannite was analyzed: Stannous tin theoretical 49.92%, found-47.60%. Fluoride theoretical-23.97%, found23.l%. Carbon theoreticall0.l%, found 10.08. Nitrogen theoretical-5.89%, found-6.97%.

In like manner, the trifiuorostannite salts listed in column 2 are prepared by reacting equimolar quantitles of the desired .amine and hydrofluoric acid and subsequently reacting the resultant amine hydrofluorides with equimolar quantities of stannous fluoride in aqueous solution.

Several of the compounds of this invention were tested for their effect on dental enamel solubility using the following method:

Test method I Step 1.Six human cuspid or bicuspid teeth, free of decay and fillings, are cleaned with a scalpel and polished with a fluor ide free dentifrice. A portion of the roots are cut off to permit imbedding the upright tooth to the enamel margin in hot inlay casting wax contained in a beaker. Additional hot Wax is touched t-o flaw-spots on the enamel and allowed to harden. The teeth are then covered with distilled water until immediately prior to use.

Step 2.A base line solubility rate for the six teeth is obtained by totally immersing them in 40 ml. of an acid buffer solution (approximately 0.1 N lactic acidsodium lactate adjusted to pH 4.5 with NaOH) for minutes. During this time interval the beaker is immersed in a water bath kept at 37 C. and the buffer solution is stirred mechanically with a glass propeller turning at a speed of 1700 rpm. At the end of the accur-ately timed 15 minute interval, the buffer solution is removed from the teeth and set aside for analysis. The teeth are immediately rinsed with distilled water.

Step 3.--The rinsed teeth are immersed in an aqueous solution of the agent to be evaluated (40 ml.), while maintaining the system at 37 C. with stirring for a 5 minute accurately timed period. The solution is then quickly removed from the beaker, the teeth are rinsed with Water and step 2 is repeated. Chemical analysis of solutions from steps 2 and 3 for phosphate ion is undertaken using the methods of Martin, J, B. and Doty, D. M., Anal. Chem. 21, 965 (1949) or Lucena-Conde & Prat, Analytica Chemica Acta 16, 473 (1957). Comparison of the two values (decalcification of teeth by acid with and Without pre-treatment) permits calculation of a percentage reduction in enamel solubility rate. The following table sets forth the percentage reduction in enamel solubility rate effected through the use of several of the compounds of the present invention.

1 Enamel solubility reduction.

Itcan be seen that the amine trifluorostannite salts are highly effective in reducing the solubility of dental enamel. As is well known, one of the causes of caries is the demineralization of dental enamel in the presence of the biologically produced acids of the oral cavity. The relationship between reduction of enamel solubility and reduced caries incidence is well established.

The oral compositions of this invention contain at least one of the hereinbefore described trifluorostannite salts and a fluoride compatible vehicle.

The pH of the oral compositions of this invention is desirably within the range from about 3.5 to about 6.0. Above about pH 6.0 the stannous ion hydrolyze to form stannous hydroxide which has no effect in protecting dental enamel. Below about pH 3.5 the consumer characteristics of the product are altered in an undesirable way. Preferably the pH values of the compositions are maintained within the range from about 4.5 to about 5.5.

The trifluorostannite salts of amines can be used in varying concentrations in the oral compositions of this invention. For example, if the composition is of the type ordinarily applied by a dentist, such as an aqueous topical solution or prophylaxis paste, concentrations of the amine trifluorostannit sufficient to provide from about p.p.m. to 7500 p.p.m. of fluoride ion can be used. In toothpaste, tooth powder, mouthwash and the like, concentrations providing from about 100 p.p.m. to about 4000 p.p.m. of fluoride ion can be employed. Preferably these compounds are present in an amount sufiicient to provide from about 500 to 2,000 parts of fluoride ion per million parts of the total composition in products intended for unsupervised use by the consumer.

Dentifrice compositions containing the amine trifluorostannites constitute a preferred embodiment of this invention. Desirably, such dentifrice compositions will be formulated with components possessed of a high level of ionic compatibility so that the stability of the product is maintained. For example, compatible abrasive materials such as particulate condensation products of melamine and urea or formaldehyde which do not form insoluble salts with fluoride ions or inactive stannous and fluoride ions by adsorption are preferred. Other abrasives which are practical both from the standpoint of compatibility and availability and which are desirable for use in the dentifrice compositions of this invention include calcium pyrophosphate, insoluble metaphosphates and alumina.

Toothpastes require binder substances to impart desired texture properties. Natural gum binders such as gum tragacanth, gum karaya, gum arabic, etc. and seaweed derivatives such as irish moss and alginates and water soluble cellulose derivatives such as hydroxyethyl cellulose and sodium carboxymethyl cellulose can be used for this purpose. Desirably those materials are employed which are most compatible with stannous and fluoride ions. Binders which have no ionic groups such as hydroxyethyl cellulose are especially preferred. Improvements in texture can also be attained by including an additional material such as colloidal magnesium aluminum silicate.

Dentifrices conventionally contain sudsing agents, although these are not critical in the practice of the present invention. Any of the commonly used sudsing agents can be used if they are reasonably stable and form suds within the pH range of the dentifrices of this invention. Examples of suitable sudsing agents include, but are not limited to, water-soluble alkyl and alkyl ether sulfonate and sulfates having alkyl groups of from about 8 to 18 carbon atoms, such as sodium lauryl sulfate, water-soluble salts of sulfonated monoglycerides of fatty acids having from 10 to 18 carbon atoms, such as sodium coconut monoglyceride sulfonate, salts of fatty acid amides of taurines such as sodium-N-methyl-N-palmitoyl tauride, salts of fatty acid esters of isethionic acid, and substantially saturated aliphatic acyl amides of saturated aliphatic monoaminocarboxylic acids having 2 to 6 carbon atoms and in which the acyl radical contains 12 to 16 carbon r J atoms, such as sodium N-lauroyl sarcoside. Mixtures of two or more sudsing agents can also be used.

Sudsing agents in an amount of from 0.5% to 5.0%

by weight of dentifrice, can be used in dentifrices of this invention.

It is also desirable to include some humectant material in a toothpaste to keep it from hardening. Materials commonly used for this purpose include glycerine, sorbitol, and other polyhydric alcohols.

Flavoring materials which can be included in toothpaste formulations include small amounts of oils of wintergreen and peppermint and sweetening agents such as saccharin, dextrose and levulose.

The dentifrice compositions of this invention will preferably contain a quantity of an amine trifluorostannite sufiicient to provide at least about 100 p.p.m. of fluoride ions but not more than 4000 p.p.m. total fluorine.

Several oral compositions for caries prophylaxis containing the amine trifluorostannites of this invention were prepared. Each composition was formulated to provide a compatible milieu for the active agent.

EXAMPLE XIII A toothpaste composition was prepared in accordance with the present invention having the following formulation.

pH=4.8 (measurement made on a slurry made up of 1 part paste and 3 parts distilled water by volume).

The above composition possesses excellent consumer characteristics and eifectively reduces the solubility of dental enamel in acid. This toothpaste will substantially reduce the incidence of dental caries when used in conjunction with a program of sound oral hygiene and regular professional care. The amine trifluorostannite employed in this example can be replaced with equimolar quantities of dodecanolamine trifiuorostannite, diethanolamine trifluorostannite or triethanolamine trifluorostannite without loss of anticaries effect or impairment of consumer characteristics.

EXAMPLE XIV A mouthwash, which constitutes another embodiment of this invention, is prepared having the following formulation.

Percent by Component: weight Ethyl alcohol 20.00 Glycerine 10.00 Dodecylarnine trifluorostannite 0.20

Polyoxyethylene sorbitan monooleate (emulsifier) 0.20

Minor ingredients 1.25 Water 68.35

Total 100.00

This composition when retained in the oral cavity 1 to 2 minutes each day constitutes an effective caries prophylactic. Any of the other amine trifluorostannites disclosed herein or mixtures thereof can be used in place of dodeoylamine trifluorostannite. For example, 0.2% of propylamine trifluorostannite, octylamine trifluorostannite or tetradecylamine trifiuorostannite can be used in the foregoing composition with no substantial change in activity. The composition maintains its anticaries activity over a long period of time.

EXAMPLE XV A tooth powder embodying the invention is formulated as follows:

Insoluble sodium metaphosphate 35.11 Calcium pyrophosphate 60.00 Sodium coconut alkyl sulfate 3.00 N-octadecyl N hydroxyethyl N di(hydroxyethyl)-propylene diamine trifluorostannite .44 Flavor 1.45

This formulation is effective in caries prophylaxis, has good consumer characteristics, and remains active for long periods of time. The trifluorostannite salt employed in this example can be replaced with equimolar quantities of any of the t-rifluorostannite salts listed in column 2 with no significant change in anticaries activity.

Although the foregoing examples of oral compositions for caries prophylaxis are directed to products which are ordinarily used in the home, it is to be understood that compositions which are usually applied by the dentist also constitutes embodiments of this invention. For example, dental prophylaxis pastes employed by dentist in cleaning teeth and containing the usual pumice and flavoring components can be formulated to contain in addition, 7.2% of methyldiethanolamine triiiuorostannite, trimethylamine trifluorostannite, diisopropanolamine trifluorostannite, dodecylaminoethyl trifluorostannite, or ethylene diamine trifluorostannite. The pH of the composition is adjusted to 6.0 with a citric acid-sodium citrate buffer solution. Such compositions employed in the usual manner by the dentist are of exceptional value in caries prophylaxis.

Aqueous solutions of the amine trifluorostannite salts of this invention designed to be topically applied to the teeth by the dentist are also etficacious compositions for caries prophylaxis. Such compositions can also contain flavoring materials and the like. The concentration of the trifluorostannite salts of amines in such a composition is within the range from about 0.14% to about 7.0% and the pH of the solution is the range from about 3.5 to about 6.0.

It is understood that the compositions of this invention can contain, in addition to the usual components of such formulation, functional adjuvants such as antibacterial, deodorizing and medicinal agents.

What is claimed is:

1. An oral composition for caries prophylaxis comprising an amine trifluorostannite having the formula:

a Rr f wherein R R and R are each members selected from the group consisting of hydrogen, alkyl, hydroxyalkyl, and aminoalkyl groups, at least one of said Rs being one of said groups containing from about 1 to about 18 carbon atoms, the total carbon content of said groups being less than 30 carbon atoms in a quantity sufficient to provide at least about p.p.m. of fluoride ions but not more than 7500 p.p.m. total fluorine, and a fluoride compatible abrasive, the pH of said composition being within the range from about 3.5 to about 6.0 in aqueous solution.

2. The composition of claim 1 wherein the amine trifluorostannite is N-octadecyl-N-hydroxyethyl-N-di(hydroxyethyl)-propylene diamine trifinorostannite.

3. The composition of claim 1 wherein the amine trifluorostannite is monoethanolamine trifluorostannite.

7 4. The composition of claim 1 wherein the amine 3,085,102 4 4/63 Yatagai et a1. r 260-429] tnfluorostanmte 1s d1ethano1arn1ne tnfluorostanmte. OTHER REFERENCES 5. The composition of claim 1 wherein the amine trifluorostannite is triethanolaminee trifiuorostannite. I Gershon 6t D g and Cosmetic Industry, 82,

5 No. 2, pages 160, 161, and 251-257, February 1958.

References Cited by the Examiner JULIAN S. LEVITT, Primary Examiner.

UNITED STATES PATENTS 2,836,544 5/58 Nebergall 16793 FRANK CACCIAPAGLIA gggi 3,070,615 12/ 2 Seyferth 260--429.7 3,083,143 3/63 Schmid et a1. 167--93 

1. AN ORAL COMPOSITION FOR CARIES PROPHYLAXIS COMPRISING AN AMINE TRIFLUOROSTANNITE HAVING THE FORMULA: 